Fluorides were added to the water supply of a school in Seagrove, North Carolina. The concentration of fluoride used was higher than the level considered optimal for community water fluoridation in the geographic area. Children attending the Seagrove school live in an area without a central water supply and where the various sources of well water contain negligible levels of fluoride. Children are exposed to the higher fluoride level only while at school in an attempt to approximate the total fluoride intake of children who drink optimally fluoridated water on a full-time basis. Baseline dental examinations for dental caries were made prior to the installation of fluoridation equipment. Follow-up examinations are conducted after four, eight, and twelve years to determine the extent of caries protection as increasingly larger segments of the study population become continuously exposed to fluoridated water at school since entering the first grade. Results of the four-year examinations showed appreciable decreases in caries prevalence compared with baseline findings. On the eight-year examinations, an assessment of the prevalence of dental fluorosis, if any, was made along with the regular examinations for dental caries. No children showed any definite signs of the condition. NIDR Classification: 10550.